#include<bits/stdc++.h>
using namespace std;
#define endl '\n'
const int MAXN=1e5;
long long bit[MAXN+1]={0};
void update(int i,int x){
for(;i<=MAXN;i+=(i&(-i))){
bit[i]+=x;
}
}
long long query(int i){
long long curr=0;
for(;i;i-=(i&(-i))){
curr+=bit[i];
}
return curr;
}
long long range(int l,int r){
return (query(r)-query(l-1));
}
int in[MAXN+1],out[MAXN+1];
int tim=1;
vector<vector<int>> graph(MAXN+1);
int sparse[18][2*MAXN+1];
int timLCA=0;
int depth[MAXN+1];
int loga[2*MAXN+1];
int fir[MAXN+1];
int cmpLCA(int u,int v){
if(depth[u]<depth[v]){
return u;
}
return v;
}
int LCA(int u,int v){
int l=fir[u],r=fir[v];
if(l>r){
swap(l,r);
}
return cmpLCA(sparse[loga[r-l+1]][l],sparse[loga[r-l+1]][r-(1<<loga[r-l+1])+1]);
}
void DFS(int u,int p){
in[u]=tim;
tim++;
sparse[0][timLCA]=u;
fir[u]=timLCA;
timLCA++;
for(int v:graph[u]){
if(v!=p){
depth[v]=depth[u]+1;
DFS(v,u);
}
}
out[u]=tim-1;
if(p!=-1){
sparse[0][timLCA]=p;
timLCA++;
}
}
struct inter{
int low,high,s,t,idx;
};
bool cmp(inter &a,inter &b){
return (((a.low+a.high)>>1)<((b.low+b.high)>>1));
}
bool bruh(pair<int,int> &a,pair<int,int> &b){
return (a.second<b.second);
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
loga[1]=0;
for(int i=2;i<=2*MAXN;i++){
loga[i]=loga[i>>1]+1;
}
depth[1]=0;
int n,m,q;
cin >> n >> m >> q;
vector<pair<int,int>> edges;
edges.push_back({0,0});
for(int i=0;i<n-1;i++){
int a,b;
cin >> a >> b;
edges.push_back({a,b});
graph[a].push_back(b);
graph[b].push_back(a);
}
DFS(1,-1);
for(int i=1;i<18;i++){
for(int j=0;j+(1<<i)<=timLCA;j++){
sparse[i][j]=cmpLCA(sparse[i-1][j],sparse[i-1][j+(1<<(i-1))]);
}
}
vector<pair<int,int>> chk(m);
for(int i=0;i<m;i++){
cin >> chk[i].first >> chk[i].second;
}
sort(chk.begin(),chk.end(),bruh);
long long gold[q],sil[q];
vector<inter> que(q);
for(int i=0;i<q;i++){
cin >> que[i].s >> que[i].t >> gold[i] >> sil[i];
que[i].idx=i;
que[i].low=0,que[i].high=m-1;
que[i].low--,que[i].high++;
}
vector<inter> temp2;
while(!que.empty()){
sort(que.begin(),que.end(),cmp);
for(int i=1;i<=n;i++){
bit[i]=0;
}
int ptr=-1;
vector<inter> temp;
for(inter &x:que){
if(x.high-x.low<=1){
temp2.push_back(x);
continue;
}
inter nxt=x;
int mid=((x.low+x.high)>>1);
while(ptr<mid){
ptr++;
int u=edges[chk[ptr].first].first,p=edges[chk[ptr].first].second;
if(depth[u]<depth[p]){
swap(u,p);
}
update(in[u],chk[ptr].second);
if(out[u]+1<=MAXN){
update(out[u]+1,-chk[ptr].second);
}
}
long long sum=query(in[x.s])+query(in[x.t])-2*query(in[LCA(x.s,x.t)]);
if(sum<=sil[x.idx]){
nxt.low=mid;
}
else{
nxt.high=mid;
}
temp.push_back(nxt);
}
que=temp;
}
sort(temp2.begin(),temp2.end(),cmp);
int ans[q];
for(int i=1;i<=n;i++){
bit[i]=0;
}
for(int ptr=0;ptr<m;ptr++){
int u=edges[chk[ptr].first].first,p=edges[chk[ptr].first].second;
if(depth[u]<depth[p]){
swap(u,p);
}
update(in[u],1);
if(out[u]+1<=MAXN){
update(out[u]+1,-1);
}
}
int ptr=-1;
for(inter &x:temp2){
while(ptr<x.low){
ptr++;
int u=edges[chk[ptr].first].first,p=edges[chk[ptr].first].second;
if(depth[u]<depth[p]){
swap(u,p);
}
update(in[u],-1);
if(out[u]+1<=MAXN){
update(out[u]+1,1);
}
}
long long sum=query(in[x.s])+query(in[x.t])-2*query(in[LCA(x.s,x.t)]);
if(sum<=gold[x.idx]){
ans[x.idx]=gold[x.idx]-sum;
}
else{
ans[x.idx]=-1;
}
}
for(int i=0;i<q;i++){
cout << ans[i] << endl;
}
}
